Specification:Material: ABS.Battery: Lithium.Energy: 1200 mah.Power: 5V.Charging: USB.Charging time: 3.5hours. More features:One key design-Long press 3seconds to turn on the machine, one press to switch 2speeds or turn off.Easy to use-Just need choose one suitable roller to install on the body and turn on to use.Automatic Power-off Protection -When you apply too much pressure, the motor overheats or the roller head is stuck by cloth or hair, etc, the device will shut down automatically to protect your skin. Where to need Foot Callus Remover?- Rough chapped heels.- Corn.- Parched skin.- Thick toe.- Painful foot calluses.- Cracked skin.- Stubborn skin for the elderly.- Long-term exercise, running, climbing callused. How to make baby-skin feet?1. Soak feet in warm water for 10mins then wipe it clean.2. According to the condition of your skin, choose the appropriate grinding head to install on the body and slide over the callused gently.3. Wipe feet with dry cloth or clean the dead skin, apply moisturizing cream, massage feet slowly.How to replace roller head:To replace roller head, ensure the unit is turned off and remove from the unit by pressing the eject button on the side of the unit. Tips:1. Please do not stay in one skin area for more than 3seconds to avoid damaging your weak skin.2. Please closing the foot file, than clean the grinding heads.3. Head can be washed under the faucet, but do not all in water.4. Grinding head is only suitable for hard and thick skin, such as heel, please not be used in other parts of the body. Pack included:1x Foot File.2 x Grinding Head.1x Head Protector Case.1x USB Cable.1x Cleaning Brush.1x User Manual.